1. Field of the Invention
The present invention relates to image processing apparatuses and control methods thereof.
2. Description of the Related Art
Depending on the application of a captured image, shooting conditions, or the like, image signals are sometimes read out from only some pixels of an image sensor, rather than from all pixels of the image sensor. In such a case, the signals from a plurality of pixels having the same color are added together and read out, the pixels are thinned and read out, or the like.
However, the logical spatial positions of image signals resulting from summation readout, thinning readout, or the like (that is, virtual pixel positions obtained from the positions of summed pixels) are not at equal intervals. Such positional skew is called “center deviation”, and center deviation is a cause of jaggies (step-like artifacts found at the edges of sloped lines and so on), which reduce the image quality.
In response to such a problem, Japanese Patent Laid-Open No. 2008-199177 and Japanese Patent Laid-Open No. 2011-97541 disclose techniques for obtaining a weighted sum of same-color pixels resulting from summation readout and correcting the center positions of the summed pixels.
However, positional correction through obtaining a weighted sum using only same-colored pixels, as disclosed in Japanese Patent Laid-Open No. 2008-199177 and Japanese Patent Laid-Open No. 2011-97541, cannot be said to have sufficient effects with respect to ameliorating jaggies through the correction, and there is still room for improvement.
The present invention provides an image processing apparatus and control method thereof capable of more effectively ameliorating jaggies.